Sphincter treatment apparatus

ABSTRACT

A sphincter treatment apparatus includes an energy delivery device introduction member including a proximal end with a first radius of curvature and a distal end with a second radius of curvature. The introduction member is configured to be introduced into the sphincter in a non-deployed state and to be expanded to a deployed state to at least partially expand the sphincter or an adjoining structure. An energy delivery device is coupled to the introduction member. A retainer member is coupled to the energy delivery device introduction member and configured to controllably position the introduction member in an orifice of the sphincter.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/175,471, filed 6 Jul. 2005, which is a continuation of U.S. patentapplication Ser. No. 10/405,746, filed Apr. 2, 2003, now abandoned,which is a continuation of U.S. patent application Ser. No. 09/943,646,filed Aug. 30, 2001, now abandoned, which is a continuation of U.S.patent application Ser. No. 09/070,490, filed Apr. 30, 1998, nowabandoned, which is a continuation-in-part of U.S. patent applicationSer. No. 09/026,316, filed Feb. 19, 1998, now U.S. Pat. No. 6,056,744.

FIELD OF THE INVENTION

This invention relates generally to an apparatus for the treatment ofsphincters, and more specifically to an apparatus that treats esophagealsphincters.

DESCRIPTION OF RELATED ART

Gastroesophageal reflux disease (GERD) is a common gastroesophagealdisorder in which the stomach contents are ejected into the loweresophagus due to a dysfunction of the lower esophageal sphincter (LES).These contents are highly acidic and potentially injurious to theesophagus resulting in a number of possible complications of varyingmedical severity. The reported incidence of GERD in the U.S. is as highas 10% of the population (Castell D O; Johnston B T: GastroesophagealReflux Disease: Current Strategies For Patient Management. Arch Fam Med,5(4):221-7; (1996 April)).

Acute symptoms of GERD include heartburn, pulmonary disorders and chestpain. On a chronic basis, GERD subjects the esophagus to ulcerformation, or esophagitis and may result in more severe complicationsincluding esophageal obstruction, significant blood loss and perforationof the esophagus. Severe esophageal ulcerations occur in 20-30% ofpatients over age 65. Moreover, GERD causes adenocarcinoma, or cancer ofthe esophagus, which is increasing in incidence faster than any othercancer (Reynolds J C: Influence Of Pathophysiology, Severity, And CostOn The Medical Management Of Gastroesophageal Reflux Disease. Am JHealth Syst Pharm, 53(22 Suppl 3):55-12 (1996 Nov. 15)).

One of the possible causes of GERD may be aberrant electrical signals inthe LES or cardia of the stomach. Such signals may cause a higher thannormal frequency of relaxations of the LES allowing acidic stomachcontents to be repeatedly ejected into the esophagus and cause thecomplications described above. Research has shown that unnaturalelectrical signals in the stomach and intestine can cause reflux eventsin those organs (Kelly K A, et al: Duodenal-gastric Reflux and SlowedGastric Emptying by Electrical Pacing of the Canine Duodenal PacesetterPotential. Gastroenterology. 1977 March; 72(3): 429-433). In particular,medical research has found that sites of aberrant electrical activity orelectrical foci may be responsible for those signals (Karlstrom L H, etal.: Ectopic Jejunal Pacemakers and Enterogastric Reflux after RouxGastrectomy: Effect Intestinal Pacing. Surgery. 1989 September; 106(3):486-495). Similar aberrant electrical sites in the heart which causecontractions of the heart muscle to take on life threatening patterns ordysrhythmias can be identified and treated using mapping and ablationdevices as described in U.S. Pat. No. 5,509,419. However, there is nocurrent device or associated medical procedure available for theelectrical mapping and treatment of aberrant electrical sites in the LESand stomach as a means for treating GERD.

Current drug therapy for GERD includes histamine receptor blockers whichreduce stomach acid secretion and other drugs which may completely blockstomach acid. However, while pharmacologic agents may provide short termrelief, they do not address the underlying cause of LES dysfunction.

Invasive procedures requiring percutaneous introduction ofinstrumentation into the abdomen exist for the surgical correction ofGERD. One such procedure, Nissen fundoplication, involves constructing anew “valve” to support the LES by wrapping the gastric fundus around thelower esophagus. Although the operation has a high rate of success, itis an open abdominal procedure with the usual risks of abdominal surgeryincluding: postoperative infection, herniation at the operative site,internal hemorrhage and perforation of the esophagus or of the cardia.In fact, a recent 10 year, 344 patient study reported the morbidity ratefor this procedure to be 17% and mortality 1% (Urschel, J D:Complications Of Antireflux Surgery, Am J Surg 166(1): 68-70; (1993July)). This rate of complication drives up both the medical cost andconvalescence period for the procedure and may exclude portions ofcertain patient populations (e.g., the elderly and immuno-compromised).

Efforts to perform Nissen fundoplication by less invasive techniqueshave resulted in the development of laparoscopic Nissen fundoplication.Laparoscopic Nissen fundoplication, reported by Dallemagne et al.Surgical Laparoscopy and Endoscopy, Vol. 1, No. 3, (1991), pp. 138-43and by Hindler et al. Surgical Laparoscopy and Endoscopy, Vol. 2, No. 3,(1992), pp. 265-272, involves essentially the same steps as Nissenfundoplication with the exception that surgical manipulation isperformed through a plurality of surgical cannula introduced usingtrocars inserted at various positions in the abdomen.

Another attempt to perform fundoplication by a less invasive techniqueis reported in U.S. Pat. No. 5,088,979. In this procedure aninvagination device containing a plurality of needles is insertedtransorally into the esophagus with the needles in a retracted position.The needles are extended to engage the esophagus and fold the attachedesophagus beyond the gastroesophageal junction. A remotely operatedstapling device, introduced percutaneously through an operating channelin the stomach wall, is actuated to fasten the invaginatedgastroesophageal junction to the surrounding involuted stomach wall.

Yet another attempt to perform fundoplication by a less invasivetechnique is reported in U.S. Pat. No. 5,676,674. In this procedure,invagination is done by a jaw-like device and fastening of theinvaginated gastroesophageal junction to the fundus of the stomach isdone via a transoral approach using a remotely operated fasteningdevice, eliminating the need for an abdominal incision. However, thisprocedure is still traumatic to the LES and presents the postoperativerisks of gastroesophageal leaks, infection and foreign body reaction,the latter two sequela resulting when foreign materials such as surgicalstaples are implanted in the body.

While the methods reported above are less invasive than an open Nissenfundoplication, some still involve making an incision into the abdomenand hence the increased morbidity and mortality risks and convalescenceperiod associated with abdominal surgery. Others incur the increasedrisk of infection associated with placing foreign materials into thebody. All involve trauma to the LES and the risk of leaks developing atthe newly created gastroesophageal junction.

Besides the LES, there are other sphincters in the body which if notfunctionally properly can cause disease states or otherwise adverselyaffect the lifestyle of the patient. Reduced muscle tone or otherwiseaberrant relaxation of sphincters can result in a laxity of tightnessdisease states including, but not limited to, urinary incontinence.

There is a need to provide an apparatus to treat a sphincter and reducea frequency of sphincter relaxation. Another need exists for anapparatus to create controlled cell necrosis in a sphincter tissueunderlying a sphincter mucosal layer. Yet another need exists for anapparatus to create cell necrosis in a sphincter and minimize injury toa mucosal layer of the sphincter. There is another need for an apparatusto controllably produce a lesion in a sphincter without creating apermanent impairment of the sphincter's ability to achieve aphysiologically normal state of closure. Still a further need exists foran apparatus to create a tightening of a sphincter without permanentlydamaging anatomical structures near the sphincter. There is stillanother need for an apparatus to create cell necrosis in a loweresophageal sphincter to reduce a frequency of reflux of stomach contentsinto an esophagus.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide anapparatus to treat a sphincter and reduce a frequency of sphincterrelaxation.

Another object of the invention is to provide an apparatus to createcontrolled cell necrosis in a sphincter tissue underlying a sphinctermucosal layer.

Yet another object of the invention is to provide an apparatus to createcell necrosis in a sphincter and minimize injury to a mucosal layer ofthe sphincter.

A further object of the invention is to provide an apparatus tocontrollably produce a lesion in a sphincter without creating, apermanent impairment of the sphincter's ability to achieve aphysiologically normal state of closure.

Still another object of the invention is to provide an apparatus tocreate a tightening of a sphincter without permanently damaginganatomical structures near the sphincter.

Another object of the invention is to provide an apparatus to createcell necrosis in a lower esophageal sphincter to reduce a frequency ofreflux of stomach contents into an esophagus.

Yet another object of the invention is to provide an apparatus to reducethe frequency and severity of gastroesophageal reflux events.

These and other objects of the invention are provided in a sphinctertreatment apparatus. The apparatus includes an energy delivery deviceintroduction member including a proximal end with a first radius ofcurvature and a distal end with a second radius of curvature greaterthan the first radius of curvature. The energy delivery deviceintroduction member is configured to be introduced into the sphincter ina non-deployed state and to be expanded to a deployed state to at leastpartially expand the sphincter or an adjoining structure. An energydelivery device is coupled to the energy delivery device introductionmember. A retainer member is coupled to the energy delivery deviceintroduction member and configured to controllably position the energydelivery device introduction member in an orifice of the sphincter.

In one embodiment, the energy delivery device has a distal portion thatis introducible into an interior of the sphincter.

In another embodiment, the energy delivery device is an RF needleelectrode.

In one embodiment, the energy delivery device introduction membercomprises a balloon.

In another embodiment, the energy delivery device introduction member isa basket assembly.

In one embodiment, the retainer member is an endoscope made of polymericmaterial.

In another embodiment, the retainer member at least partially surroundsthe energy delivery device introduction member and includes a slot toenhance an engagement of the introduction member with the sphincter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrated lateral view of the upper GI tract includingthe esophagus and lower esophageal sphincter and the positioning of thesphincter treatment apparatus of the present invention in the loweresophageal sphincter.

FIG. 2A is a lateral view of the present invention illustrating theenergy delivery device, power supply and expansion device in an expandedand contracted state.

FIG. 2B is a lateral view of an embodiment of the invention illustratingthe use of a slotted introducer to facilitate contact of the expansiondevice with esophageal wall.

FIG. 3 depicts a lateral view of the present invention that illustratescomponents on the flexible shaft including a proximal fitting,connections and proximal and distal shaft segments.

FIG. 4A illustrates a lateral view of the basket assembly used in anembodiment of the invention.

FIG. 4B illustrates a lateral view of a basket assembly with a taperedtip.

FIG. 5A is a lateral view of the basket assembly that illustrates therange of camber in the basket assembly.

FIG. 5B is a perspective view illustrating a balloon coupled to thebasket assembly.

FIG. 6A is a lateral view of the junction between the basket arms andthe shaft illustrating the pathway used for advancement of the movablewire or the delivery of fluids.

FIG. 6B is a frontal view of a basket arm in an alternative embodimentof the invention illustrating a track in the arm used to advance themovable wire.

FIG. 7 is a cross-sectional view of a section of the basket armillustrating stepped and tapered sections in basket arm apertures.

FIG. 8 is a lateral view of the basket assembly illustrating theplacement of the radial supporting member.

FIG. 9A is a lateral view of the sphincter treatment apparatusillustrating the mechanism used in one embodiment of the invention toincrease the camber of the basket assembly.

FIG. 9B is a similar view to 9A showing the basket assembly in anincreased state of camber.

FIG. 10 is a lateral view of the sphincter treatment apparatusillustrating the deflection mechanism.

FIG. 11 is a lateral view illustrating the use of electrolytic solutionto create an enhanced RF electrode.

FIG. 12 is a lateral view of the basket assembly illustrating the use ofneedle electrodes.

FIG. 13 is a lateral view illustrating the use of an insulation segmenton the needle electrode to protect an area of tissue from RF energy.

FIG. 14 is a lateral view illustrating the placement of needleelectrodes into the sphincter wall by expansion of the basket assembly.

FIG. 15 is a lateral view illustrating placement of needle electrodesinto the sphincter wall by advancement of an electrode delivery memberout of apertures in the basket arms.

FIG. 16 is a cross sectional view illustrating the configuration of abasket arm aperture used to select and maintain a penetration angle ofthe needle electrode into the sphincter wall.

FIG. 17A is a lateral view illustrating placement of needle electrodesinto the sphincter wall by advancement of an electrode delivery memberdirectly out of the distal end of the shaft.

FIG. 17B is a lateral view illustrating the use of a needle hub tofacilitate placement of needle electrodes into the sphincter wall.

FIG. 18 A is a lateral view illustrating a radial distribution ofelectrodes on the expansion device of the invention.

FIG. 18B is a lateral view illustrating a longitudinal distribution ofelectrodes on the expansion device of the invention.

FIG. 18C is a lateral view illustrating a spiral distribution ofelectrodes on the expansion device of the invention.

FIG. 19 is a flow chart illustrating a sphincter treatment method usingthe apparatus of the present invention.

FIG. 20 is a lateral view of sphincter smooth muscle tissue illustratingelectromagnetic foci and pathways for the origination and conduction ofaberrant electrical signals in the smooth muscle of the lower esophagealsphincter or other tissue.

FIG. 21 is a lateral view of a sphincter wall illustrating theinfiltration of tissue healing cells into a lesion in the smooth tissueof a sphincter following treatment with the sphincter treatmentapparatus of the present invention.

FIG. 22 is a view similar to that of FIG. 21 illustrating shrinkage ofthe lesion site caused by cell infiltration.

FIG. 23 is a lateral view of the esophageal wall illustrating thepreferred placement of lesions in the smooth muscle layer of aesophageal sphincter.

FIG. 24 is a lateral view illustrating the ultrasound transducer,ultrasound lens and power source of an embodiment of the presentinvention.

FIGS. 25A-D are lateral views of the sphincter wall illustrating variouspatterns of lesions created by the apparatus of the present invention.

FIG. 26 is a lateral view of the sphincter wall illustrating thedelivery of cooling fluid to the electrode-tissue interface and thecreation of cooling zones.

FIG. 27 depicts the flow path, fluid connections and control unitemployed to deliver fluid to the electrode-tissue interface.

FIG. 28 depicts the flow path, fluid connections and control unitemployed to deliver fluid to the RF electrodes.

FIG. 29 is an enlarged lateral view illustrating the placement ofsensors on the expansion device or basket assembly.

FIG. 30 depicts a block diagram of the feed back control system that canbe used with the sphincter treatment apparatus.

FIG. 31 depicts a block diagram of an analog amplifier, analogmultiplexer and microprocessor used with the feedback control system ofFIG. 30.

FIG. 32 depicts a block diagram of the operations performed in thefeedback control system depicted in FIG. 30.

DETAILED DESCRIPTION

Referring now to FIGS. 1 and 2, one embodiment of sphincter treatmentapparatus 10 that is used to deliver energy to a treatment site 12 toproduce lesions in a sphincter 16, such as the lower esophagealsphincter (LES), comprises a flexible elongate shaft 18, also calledshaft 18, coupled to a expansion device 20, in turn coupled with one ormore energy delivery devices 22. Energy delivery devices 22 areconfigured to be coupled to a power source 24. The expansion device 20is configured to be positionable in a sphincter 16 such as the LES oradjacent anatomical structure, such as the cardia of the stomach.Expansion device 20 is further configured to facilitate the positioningof energy delivery devices 22 to a selectable depth in a sphincter wall26 or adjoining anatomical structure. Expansion device 20 has a centrallongitudinal axis 28 and is moveable between contracted and expandedpositions substantially there along. This can be accomplished by aratchet mechanism as is known to those skilled in the art. At leastportions of sphincter treatment apparatus 10 may be sufficientlyradiopaque in order to be visible under fluoroscopy and/or sufficientlyechogenic to be visible under ultrasonography. Also as will be discussedherein, sphincter treatment apparatus 10 can include visualizationcapability including, but not limited to, a viewing scope, an expandedeyepiece, fiber optics, video imaging and the like.

Referring to FIG. 2A, shaft 18 is configured to be coupled to expansiondevice 20 and has sufficient length to position expansion device 20 inthe LES and/or stomach using a transoral approach. Typical lengths forshaft 18 include, but are not limited to, a range of 40-180 cms. Invarious embodiments, shaft 18 is flexible, articulated and steerable andcan contain fiber optics (including illumination and imaging fibers),fluid and gas paths, and sensor and electronic cabling. In oneembodiment, shaft 18 can be a multi-lumen catheter, as is well known tothose skilled in the art.

In another embodiment, an introducing member 21, also called anintroducer, is used to introduce sphincter treatment apparatus 10 intothe LES. Introducer 21 can also function as a sheath for expansiondevice 20 to keep it in a nondeployed or contracted state duringintroduction into the LES. In various embodiments, introducer 21 isflexible, articulated and steerable and contains a continuous lumen ofsufficient diameter to allow the advancement of sphincter treatmentapparatus 10. Typical diameters for introducer 21 include 0.1 to 2inches, while typical length include 40-180 cms. Introducer 21 may be ofsufficient length and width to extend into a portion of or past the LESand provide structural support to and/or immobilize the esophagus. Thisserves to reduce movement of the esophagus and/or expansion device 20 soas to facilitate introduction of a needle electrode (described herein)into sphincter wall 26. As shown in FIG. 2B, introducer 21 may alsocontain slots 25 near introducer distal end 21′ or at other points alongits length. Slots 25 are of sufficient length and width to allowexpansion device 20 to engage sphincter wall 26 when it is put into adeployed state inside introducer 21. Suitable materials for introducer21 include coil-reinforced plastic tubing as is well known to thoseskilled in the art.

Referring now to FIG. 3, the flexible elongate shaft 18 is circular incross section and has proximal and distal extremities (also called ends)30 and 32. Shaft 18 may also be coupled at its proximal end 32 to aproximal fitting 34, also called a handle; used by the physician tomanipulate sphincter treatment apparatus 10 to reach treatment site 12.Shaft 18 may have one or more lumens 36, that extend the full length ofshaft 18, or part way from shaft proximal end 30 to shaft distal end 32.Lumens 36 may be used as paths for catheters, guide wires, pull wires,insulated wires and cabling, fluid and optical fibers. Lumens 36 areconnected to and/or accessed by connections 38 on or adjacent toproximal fitting 34. Connections 38 can include luer-lock, lemoconnector, swage and other mechanical varieties well known to thoseskilled in the art. Connections 38 can also include optical/videoconnections which allow optical and electronic coupling of opticalfibers and/or viewing scopes to illuminating sources, eye pieces andvideo monitors. In various embodiments, shaft 18 may stop at theproximal extremity 40 of expansion device 20 or extend to, or past, thedistal extremity 42 of expansion device 20. Suitable materials for shaft18 include, but are not limited to, polyethylenes, polyurethanes andother medical plastics known to those skilled in the art.

Referring now to FIG. 4A, in one embodiment of the present inventionexpansion device 20 comprises one or more elongated arms 44 that arejoined at their proximal ends 46 and distal ends 48 to form a basketassembly 50. Proximal arm end 46 is attached to a supporting structure,which can be the distal end 32 of shaft 18 or a proximal cap 51.Likewise, distal arm end 48 is also attached to a supporting structurewhich can be a basket cap 52 or shaft 18. In one embodiment shown inFIG. 4B, basket cap 52 can be a tapered cap 52′ to facilitate insertionthrough the folds of the LES.

Attached arms 44 may form a variety of geometric shapes including, butnot limited to, curved, rectangular, trapezoidal and triangular. Arms 44can have a variety of cross sectional geometries including, but notlimited to, circular, rectangular and crescent-shaped. Also, arms 44 areof a sufficient number (two or more), and have sufficient spring force(0.01 to 0.5 lbs. force) so as to collectively exert adequate force onsphincter wall 26 to sufficiently open and efface the folds of sphincter16 to allow treatment with sphincter treatment apparatus 10, whilepreventing herniation of sphincter wall 26 into the spaces 53 betweenarms 44. Suitable materials for arms 44 include, but are not limited to,spring steel, stainless steel, superelastic shape memory metals such asnitinol or wire reinforced plastic tubing as is well known to thoseskilled in the art. In another embodiment, arms 44 may have an externallayer of texturized material 45 that has sufficient friction toimmobilize the area near and around sphincter wall 26 contacted by arm44. Suitable materials for texturized material 45 include knittedDacron® and Dacron velour.

Referring to FIG. 5A, arms 44 can have an outwardly bowed shaped memoryfor expanding the basket assembly into engagement with sphincter wall 26with the amount of bowing, or camber 54 being selectable from a range 0to 2 inches from longitudinal axis 28 of basket assembly 50. For thecase of a curve-shaped arm 44′, expanded arms 44 are circumferentiallyand symmetrically spaced-apart. In various other embodiments (notshown), arms 44 may be asymmetrically spaced and/or distributed on anarc less than 360°. Also, arms 44 may be preshaped at time ofmanufacture or shaped by the physician.

In another embodiment shown in FIG. 5B, an expandable member 55, whichcan be a balloon, is coupled to an interior or exterior of basketassembly 50. Balloon 55 is also coupled to and inflated by lumen 36using gas or liquid. Balloon 55 may be made of a textured material, orhave a texturized layer 55′ that when engaged with sphincter wall 26,provides sufficient friction to at least partially immobilize thesurface of sphincter wall 26. Suitable materials for texturized layer55′ include knitted Dacron and Dacron velour.

Referring now to FIG. 6A, arms 44 may also be solid or hollow with acontinuous lumen 58 that may be coupled with shaft lumens 36. Thesecoupled lumens provide a path for the delivery of a fluid or electrodedelivery member 60 (also called an advancement member) from shaft 18 toany point on basket assembly 50. In various embodiments electrodedelivery member 60 can be an insulated wire, an insulated guide wire, aplastic-coated stainless steel hypotube with internal wiring or aplastic catheter with internal wiring, all of which are known to thoseskilled in the art. As shown in FIG. 6B, arms 44 may also have apartially open channel 62, also called a track 62, that functions as aguide track for electrode delivery member 60. Referring back to FIG. 6A,arms 44 may have one or more apertures 64 at any point along theirlength that permit the controlled placement of energy delivery devices22 at or into sphincter wall 26. Referring now to FIG. 7, apertures 64may have tapered sections 66 or stepped sections 68 in all or part oftheir length, that are used to control the penetration depth of energydelivery devices 22 into sphincter wall 26. Referring back to FIG. 6A,apertures 64 in combination with arm lumens 58 and shaft lumens 36 maybe used for the delivery of cooling solution 70 or electrolytic solution72 to treatment site 12 as described herein. Additionally, arms 44 canalso carry a plurality of longitudinally spaced apart radiopaque and orechogenic markers or traces, not shown in the drawings, formed ofsuitable materials to permit viewing of basket assembly 50 viafluoroscopy or ultrasonography. Suitable radiopaque materials includeplatinum or gold, while suitable echogenic materials, include gas filledmicro-particles, as described in U.S. Pat. Nos. 5,688,490 and 5,205,287.Arms 44 may also be color-coded to facilitate their identification viavisual medical imaging methods and equipment, such as endoscopicmethods, which are well known to those skilled in the art.

In another embodiment of the present invention, a supporting member 74is attached to two or more arms 44. Supporting member 74, also called astrut, can be attached to arms 44 along a circumference of basketassembly 50 as shown in FIG. 8. Apertures 64 can extend through radialsupporting member 74 in one or more places. Radial supporting member 74serves the following functions: i) facilitates opening and effacement ofthe folds of sphincter 16, ii) enhances contact of Apertures 64 withsphincter wall 26; and, iii) reduces or prevents the tendency of arms 44to bunch up. The cross sectional geometry of radial supporting member 74can be rectangular or circular, though it will be appreciated that othergeometries are equally suitable.

In one embodiment shown in FIG. 9, arms 44 are attached to basket cap 52that in turn, moves freely over shaft 18, but is stopped distally byshaft cap 78. One or more pull wires 80 are attached to basket cap 52and also to a movable fitting 82 in proximal fitting 34 of sphinctertreatment apparatus 10. When pull wire 80 is pulled back by movablefitting 82, the camber 54 of basket assembly 50 increases to 54′,increasing the force and the amount of contact applied by basketassembly 50 to sphincter wall 26 or an adjoining structure. Basketassembly 50 can also be deflected from side to side using deflectionmechanism 80. This allows the physician to remotely point and steer thebasket assembly within the body. In one embodiment shown in FIG. 10,deflection mechanism 84 includes a second pull wire 80′ attached toshaft cap 78 and also to a movable slide 86 integral to-proximal fitting34.

Turning now to a discussion of energy delivery, suitable power sources24 and energy delivery devices 22 that can be employed in one or moreembodiments of the invention include: (i) a radio-frequency (RF) sourcecoupled to an RF electrode, (ii) a coherent source of light coupled toan optical fiber, (iii) an incoherent light source coupled to an opticalfiber, (iv) a heated fluid coupled to a catheter with a closed channelconfigured to receive the heated fluid, (v) a heated fluid coupled to acatheter with an open channel configured to receive the heated fluid,(vi) a cooled fluid coupled to a catheter with a closed channelconfigured to receive the cooled fluid, (vii) a cooled fluid coupled toa catheter with an open channel configured to receive the cooled fluid,(viii) a cryogenic fluid, (ix) a resistive heating source, (x) amicrowave source providing energy from 915 MHz to 2.45 GHz and coupledto a microwave antenna, (xi) an ultrasound power source coupled to anultrasound emitter, wherein the ultrasound power source produces energyin the range of 300 KHZ to 3 GHz, or (xii) a microwave source. For easeof discussion for the remainder of this application, the power sourceutilized is an RF source and energy delivery device 22 is one or more RFelectrodes 88, also described as electrodes 88. However, all of theother herein mentioned power sources and energy delivery devices areequally applicable to sphincter treatment apparatus 10.

For the case of RF energy, RF electrode 88 may operated in eitherbipolar or monopolar mode with a ground pad electrode. In a monopolarmode of delivering RF energy, a single electrode 88 is used incombination with an indifferent electrode patch that is applied to thebody to form the other electrical contact and complete an electricalcircuit. Bipolar operation is possible when two or more electrodes 88are used. Multiple electrodes 88 may be used. These electrodes may becooled as described herein. Electrodes 88 can be attached to electrodedelivery member 60 by the use of soldering methods which are well knownto those skilled in the art. Suitable solders include Megabond Soldersupplied by the Megatrode Corporation (Milwaukee, Wis.).

Suitable electrolytic solutions 72 include saline, solutions of calciumsalts, potassium salts, and the like. Electrolytic solutions 72 enhancethe electrical conductivity of the targeted tissue at the treatment site12. When a highly conductive fluid such as electrolytic solution 72 isinfused into tissue the electrical resistance of the infused tissue isreduced, in turn, increasing the electrical conductivity of the infusedtissue. As a result, there will be little tendency for tissuesurrounding electrode 88 to desiccate (a condition described herein thatincreases the electrical resistance of tissue) resulting in a largeincrease in the capacity of the tissue to carry RF energy. Referring toFIG. 11, a zone of tissue which has been heavily infused with aconcentrated electrolytic solution 72 can become so conductive as toactually act as an enhanced electrode 88′. The effect of enhancedelectrode 88′ is to increase the amount of current that can be conductedto the treatment site 12, making it possible to heat a much greatervolume of tissue in a given time period.

Also when the power source is RF, power source 24, which will now bereferred to as RF power source 24, may have multiple channels,delivering separately modulated power to each electrode 88. This reducespreferential heating that occurs when more energy is delivered to a zoneof greater conductivity and less heating occurs around electrodes 88which are placed into less conductive tissue. If the level of tissuehydration or the blood infusion rate in the tissue is uniform, a singlechannel RF power source 24 may be used to provide power for generationof lesions 14 relatively uniform in size.

Electrodes 88 can have a variety of shapes and sizes. Possible shapesinclude, but are not limited to, circular, rectangular, conical andpyramidal. Electrode surfaces can be smooth or textured and concave orconvex. The conductive surface area of electrode 88 can range from 0.1mm2 to 100 cm2. It will be appreciated that other geometries and surfaceareas may be equally suitable. In one embodiment, electrodes 88 can bein the shape of needles and of sufficient sharpness and length topenetrate into the smooth muscle of the esophageal wall, sphincter 16 orother anatomical structure. In this embodiment shown in FIGS. 2 and 13,needle electrodes 90 are attached to arms 44 and have an insulatinglayer 92, covering an insulated segment 94 except for an exposed segment95. For purposes of this disclosure, an insulator or insulation layer isa barrier to either thermal, RF or electrical energy flow. Insulatedsegment 94 is of sufficient length to extend into sphincter wall 26 andminimize the transmission of RF energy to a protected site 97 near oradjacent to insulated segment 94 (see FIG. 13). Typical lengths forinsulated segment 94 include, but are not limited to, 1-4 mms. Suitablematerials for needle electrodes 90 include, but are not limited to, 304stainless steel and other stainless steels known to those skilled in theart. Suitable materials for insulating layer 92 include, but are notlimited to, polyimides and polyamides.

During introduction of sphincter treatment apparatus 10, basket assembly50 is in a contracted state. Once sphincter treatment apparatus 10 isproperly positioned at the treatment site 12, needle electrodes 90 aredeployed by expansion of basket assembly 50, resulting in the protrusionof needle electrodes 90 into the smooth muscle tissue of sphincter wall26 (refer to FIG. 14). The depth of needle penetration is selectablefrom a range of 0.5 to 5 mms and is accomplished by indexing movablefitting 82 so as to change the camber 54 of arm 44 in fixed incrementsthat can be selectable in a range from 0.1 to 4 mms. Needle electrodes90 are coupled to power source 24 via insulated wire 60.

In another embodiment of sphincter treatment apparatus 10 shown in FIG.15, needle electrodes 90 are advanced out of apertures 64 in basket arms44 into the smooth muscle of the esophageal wall or other sphincter 16.In this case, needle electrodes 90 are coupled to RF power source 24 byelectrode delivery member 60. In this embodiment, the depth of needlepenetration is selectable via means of stepped sections 66 or taperedsections 68 located in apertures 64. Referring to FIG. 16, apertures 64and needle electrodes 90 are configured such that the penetration angle96 (also called an emergence angle 96) of needle electrode 90 intosphincter wall 26 remains sufficiently constant during the time needleelectrode 90 is being inserted into sphincter wall 26, such that thereis no tearing or unnecessary trauma to sphincter wall tissue. This isfacilitated by the selection of the following parameters and criteria:i) the emergence angle 96 of apertures 64 which can vary from 1 to 90°,ii) the arc radius 98 of the curved section 100 of aperture 64 which canvary from 0.001 to 2 inch, iii) the amount of clearance between theaperture inner diameter 102 and the needle electrode outside diameter104 which can very between 0.001″ and 0.1″; and, iv) use of a lubricouscoating on electrode delivery member 60 such as a Teflon° or othercoatings well known to those skilled in the art. Also in thisembodiment, insulated segment 94 can be in the form of an sleeve thatmay be adjustably positioned at the exterior of electrode 90.

In another alternative embodiment shown in FIG. 17A, electrode deliverymember 60 with attached needle electrodes 90, can exit from lumen 36 atdistal shaft end 32 and be positioned into contact with sphincter wall26. This process may be facilitated by use of a hollow guiding member101, known to those skilled in the art as a guiding catheter, throughwhich electrode delivery member 60 is advanced. Guiding catheter 101 mayalso include stepped sections 66 or tapered sections 68 at it distal endto control the depth of penetration of needle electrode 90 intosphincter wall 26.

In an alternative embodiment shown in FIG. 17B, needle electrodes 90 canbe advanced through an aperture 64′ in needle hub 103 (located insidebasket assembly 50) and subsequently advanced through aperture 64 in arm44 and into sphincter wall 26. Aperture 64′ has proximal and distal ends64″ and 64′″. Also needle hub 103 is configured to be coupled todelivery member 60 or basket assembly 50 and serves as a guiding tool tofacilitate penetration of needle electrode 90 into sphincter wall 26. Inone embodiment, proximal and distal ends 64″ and 64′″ of apertures 64′are located in different planes.

RF energy flowing through tissue causes heating of the tissue due toabsorption of the RF energy by the tissue and ohmic heating due to,electrical resistance of the tissue. This heating can cause injury tothe affected cells and can be substantial enough to cause cell death, aphenomenon also known as cell necrosis. For ease of discussion for theremainder of this application, cell injury will include all cellulareffects resulting from the delivery of energy from electrode 88 up to,and including, cell necrosis. Cell injury can be accomplished as arelatively simple medical procedure with local anesthesia. In oneembodiment, cell injury proceeds to a depth of approximately 1-4 mmsfrom the surface of the mucosal layer of sphincter 16 or that of anadjoining anatomical structure.

Referring now to FIGS. 18A, 18B and 18C, electrodes 88 and/or apertures64 may be distributed in a variety of patterns along expansion device 20or basket assembly 50 in order to produce a desired placement andpattern of lesions 14. Typical electrode and aperture distributionpatterns include, but are not limited to, a radial distribution 105(refer to FIG. 18A) or a longitudinal distribution 106 (refer to FIG.18B). It will be appreciated that other patterns and geometries forelectrode and aperture placement, such as a spiral distribution 108(refer to FIG. 18C) may also be suitable. These electrodes may be cooledas described hereafter.

FIG. 19 is a flow chart illustrating one embodiment of the procedure forusing sphincter treatment apparatus 10. In this embodiment, sphinctertreatment apparatus 10 is first introduced into the esophagus underlocal anesthesia. Sphincter treatment apparatus 10 can be introducedinto the esophagus by itself or through a lumen in an endoscope (notshown), such as disclosed in U.S. Pat. Nos. 5,448,990 and 5,275,608,incorporated herein by reference, or similar esophageal access deviceknown to those skilled in the art. Basket assembly 50 is expanded andcan be done through slots 25 in introducer 21 as described herein. Thisserves to temporarily dilate the LES or sufficiently to efface a portionof or all of the folds of the LES. In an alternative embodiment,esophageal dilation and subsequent LES fold effacement can beaccomplished by insufflation of the esophagus (a known technique) usinggas introduced into the esophagus through shaft, lumen 36, or anendoscope or similar esophageal access device as described above. Oncetreatment is completed, basket assembly 50 is returned to itspredeployed or contracted state and sphincter treatment apparatus 10 iswithdrawn from the esophagus. This results in the LES returning toapproximately its pretreatment state and diameter. It will beappreciated that the above procedure is applicable in whole or part tothe treatment of other sphincters in the body.

The diagnostic phase of the procedure can be performed using a varietyof diagnostic methods, including, but not limited to, the following: (i)visualization of the interior surface of the esophagus via an endoscopeor other viewing apparatus inserted into the esophagus, (ii)visualization of the interior morphology of the esophageal wall usingultrasonography to establish a baseline for the tissue to be treated,(iii) impedance measurement to determine the electrical conductivitybetween the esophageal mucosal layers and sphincter treatment apparatus10 and (iv) measurement and surface mapping of the electropotential ofthe LES during varying time periods which may include such events asdepolarization, contraction and repolarization of LES smooth muscletissue. This latter technique is done to determine target treatmentsites 12 in the LES or adjoining anatomical structures that are actingas foci 107 or pathways 109 for abnormal or inappropriate polarizationand relaxation of the smooth muscle of the LES (Refer to FIG. 20).

In the treatment phase of the procedure, the delivery of energy totreatment site 12 can be conducted under feedback control, manually orby a combination of both. Feedback control (described herein) enablessphincter treatment apparatus 10 to be positioned and retained in theesophagus during treatment with minimal attention by the physician.Electrodes 88 can be multiplexed in order to treat the entire targetedtreatment site 12 or only a portion thereof. Feedback can be includedand is achieved by the use of one or more of the following methods: (i)visualization, (ii) impedance measurement, (iii) ultrasonography, (iv)temperature measurement; and, (v) sphincter contractile forcemeasurement via manometry. The feedback mechanism permits the selectedon-off switching of different electrodes 88 in a desired pattern, whichcan be sequential from one electrode 88 to an adjacent electrode 88, orcan jump around between non-adjacent electrodes 88. Individualelectrodes 88 are multiplexed and volumetrically controlled by acontroller.

The area and magnitude of cell injury in the LES or sphincter 16 canvary. However, it is desirable to deliver sufficient energy to thetargeted treatment site 12 to be able to achieve tissue temperatures inthe range of 55-95° C. and produce lesions 14 at depths ranging from 1-4mms from the interior surface of the LES or sphincter wall 26. Typicalenergies delivered to the esophageal wall include, but are not limitedto, a range between 100 and 50,000 joules per electrode 88. It is alsodesirable to deliver sufficient energy such that the resulting lesions14 have a sufficient magnitude and area of cell injury to cause aninfiltration of lesion 14 by fibroblasts 110, myofibroblasts 112,macrophages 114 and other cells involved in the tissue healing process(refer to FIG. 21). As shown in FIG. 22, these cells cause a contractionof tissue around lesion 14, decreasing its volume and, or altering thebiomechanical properties at lesion 14 so as to result in a tightening ofLES or sphincter 16. These changes are reflected in transformed lesion14′ shown in FIG. 19B. The diameter of lesions 14 can vary between 0.1to 4 mms. It is preferable that lesions 14 are less than 4 mms indiameter in order to reduce the risk of thermal damage to the mucosallayer. In one embodiment, a 2 mm diameter lesion 14 centered in the wallof the smooth muscle provides a 1 mm buffer zone to prevent damage tothe mucosa, submucosa and adventitia, while still allowing for cellinfiltration and subsequent sphincter tightening on approximately 50% ofthe thickness of the wall of the smooth muscle (refer to FIG. 23).

From a diagnostic standpoint, it is desirable to image the interiorsurface and wall of the LES or other sphincter 16, including the sizeand position of created lesions 14. It is desirable to create a map ofthese structures which can input to a controller and used to direct thedelivery of energy to the treatment site. Referring to FIG. 24, this canbe accomplished through the use of ultrasonography (a known procedure)which involves the use of an ultrasound power source 116 coupled to oneor more ultrasound transducers 118 that are positioned on expansiondevice 20 or basket assembly 50. An output is associated with ultrasoundpower source 116.

122 that is in turn, attached to expansion device 20, or basket assembly50. An ultrasound lens 124, fabricated on an electrically insulatingmaterial 126, is mounted over piezoelectric crystal 120. Piezoelectriccrystal 120 is connected by electrical leads 128 to ultrasound powersource 116. Each ultrasound transducer 118 transmits ultrasound energyinto adjacent tissue. Ultrasound transducers 118 can be in the form ofan imaging probe such as Model 21362, manufactured and sold by HewlettPackard Company, Palo Alto, Calif. In one embodiment, two ultrasoundtransducers 118 are positioned on opposite sides of expansion device 20or basket assembly 50 to create an image depicting the size and positionof lesion 14 in selected sphincter 16.

It is desirable that lesions 14 are predominantly located in the smoothmuscle layer of selected sphincter 16 at the depths ranging from 1 to 4mms from the interior surface of sphincter wall 26. However, lesions 14can vary both in number and position within sphincter wall 26. It may bedesirable to produce a pattern of multiple lesions 14 within thesphincter smooth muscle tissue in order to obtain a selected degree oftightening of the LES or other sphincter 16. Typical lesion patternsshown in FIGS. 25A-D include, but are not limited to, (i) a concentriccircle of lesions 14 all at fixed depth in the smooth muscle layerevenly spaced along the radial axis of sphincter 16, (ii) a wavy orfolded circle of lesions 14 at varying depths in the smooth muscle layerevenly spaced along the radial axis of sphincter 16, (iii) lesions 14randomly distributed at varying depths in the smooth muscle, but evenlyspaced in a radial direction; and, (iv) an eccentric pattern of lesions14 in one or more radial locations in the smooth muscle wall.Accordingly, the depth of RF and thermal energy penetration sphincter 16is controlled and selectable. The selective application of energy tosphincter 16 may be the even penetration of RF energy to the entiretargeted treatment site 12, a portion of it, or applying differentamounts of RF energy to different sites depending on the condition ofsphincter 16. If desired, the area of cell injury can be substantiallythe same for every treatment event.

Referring to FIG. 26, it may be desirable to cool all or a portion ofthe area near the electrode-tissue interface 130 before, during or afterthe delivery of energy in order to reduce the degree and area of cellinjury. Specifically, the use of cooling preserves the mucosal layers ofsphincter wall 26 and protects, or otherwise reduces the degree of celldamage to cooled zone 132 in the vicinity of lesion 14. Referring now toFIG. 27, this can be accomplished through the use of cooling solution 70that is delivered by apertures 64 which is in fluid communication withshaft lumen 36 that is, in turn, in fluid communication with fluidreservoir 134 and a control unit 136, whose operation is describedherein, that controls the delivery of the fluid.

Similarly, it may also be desirable to cool all or a portion of theelectrode 88. The rapid delivery of heat through electrode 88, mayresult in the build up of charred biological matter on electrode 88(from contact with tissue and fluids e.g., blood) that impedes the flowof both thermal and electrical energy from electrode 88 to adjacenttissue and causes an electrical impedance rise beyond a cutoff value seton RF power source 24. A similar situation may result from thedesiccation of tissue adjacent to electrode 88. Cooling of the electrode88 can be accomplished by cooling solution 70 that is delivered byapertures 64 as described previously. Referring now to FIG. 28,electrode 88 may also be cooled via a fluid channel 138 in electrode 88that is in fluid communication with fluid reservoir 134 and control unit136.

As shown in FIG. 29, one or more sensors 140 may be positioned adjacentto or on electrode 88 for sensing the temperature of sphincter tissue attreatment site 12. More specifically, sensors 140 permit accuratedetermination of the surface temperature of sphincter wall 26 atelectrode-tissue interface 130. This information can be used to regulateboth the delivery of energy and cooling solution 70 to the interiorsurface of sphincter wall 26. In various embodiments, sensors 140 can bepositioned at any position on expansion device 20 or basket assembly 50.Suitable sensors that may be used for sensor 140 include: thermocouples,fiber optics, resistive wires, thermocouple IR detectors, and the like.Suitable thermocouples for sensor 140 include: T type with copperconstantene, J type, E type and K types as are well known those skilledin the art.

Temperature data from sensors 140 are fed back to control unit 136 andthrough an algorithm which is stored within a microprocessor memory ofcontrol unit 136. Instructions are sent to an electronically controlledmicropump (not shown) to deliver fluid through the fluid lines at theappropriate flow rate and duration to provide control temperature at theelectrode-tissue interface 130 (refer to FIG. 27).

The reservoir of control unit 136 may have the ability to control thetemperature of the cooling solution 70 by either cooling the fluid orheating the fluid. Alternatively, a fluid reservoir 134 of sufficientsize may be used in which the cooling solution 70 is introduced at atemperature at or near that of the normal body temperature. Using athermally insulated reservoir 142, adequate control of the tissuetemperature may be accomplished without need of refrigeration or heatingof the cooling solution 70. Cooling solution 70 flow is controlled bycontrol unit 136 or another feedback control system (described herein)to provide temperature control at the electrode-tissue interface 130.

A second diagnostic phase may be included after the treatment iscompleted. This provides an indication of LES tightening treatmentsuccess, and whether or not a second phase of treatment, to all or onlya portion of the esophagus, now or at some later time, should beconducted. The second diagnostic phase is accomplished through one ormore of the following methods: (i) visualization, (ii) measuringimpedance, (iii) ultrasonography, (iv) temperature measurement, or (v)measurement of LES tension and contractile force via manometry.

In one embodiment, sphincter treatment apparatus 10 is coupled to anopen or closed loop feedback system. Referring now to FIG. 30, an openor closed loop feedback system couples sensor 346 to energy source 392.In this embodiment, electrode 314 is one or more RF electrodes 314.

The temperature of the tissue, or of RF electrode 314 is monitored, andthe output power of energy source 392 adjusted accordingly. Thephysician can, if desired, override the closed or open loop system. Amicroprocessor 394 can be included and incorporated in the closed oropen loop system to switch power on and off, as well as modulate thepower. The closed loop system utilizes microprocessor 394 to serve as acontroller, monitor the temperature, adjust the RF power, analyze theresult, refeed the result, and then modulate the power.

With the use of sensor 346 and the feedback control system a tissueadjacent to RF electrode 314 can be maintained at a desired temperaturefor a selected period of time without causing a shut down of the powercircuit to electrode 314 due to the development of excessive electricalimpedance at electrode 314 or adjacent tissue as is discussed herein.Each RF electrode 314 is connected to resources which generate anindependent output. The output maintains a selected energy at RFelectrode 314 for a selected length of time.

Current delivered through RF electrode 314 is measured by current sensor396. Voltage is measured by voltage sensor 398. Impedance and power arethen calculated at power and impedance calculation device 400. Thesevalues can then be displayed at user interface and display 402. Signalsrepresentative of power and impedance values are received by acontroller 404.

A control signal is generated by controller 404 that is proportional tothe difference between an actual measured value, and a desired value.The control signal is used by power circuits 406 to adjust the poweroutput in an appropriate amount in order to maintain the desired powerdelivered at respective RF electrodes 314.

In a similar manner, temperatures detected at sensor 346 providefeedback for maintaining a selected power. Temperature at sensor 346 isused as a safety means to interrupt the delivery of energy when maximumpre-set temperatures are exceeded. The actual temperatures are measuredat temperature measurement device 408, and the temperatures aredisplayed at user interface and display 402. A control signal isgenerated by controller 404 that is proportional to the differencebetween an actual measured temperature and a desired temperature. Thecontrol signal is used by power circuits 406 to adjust the power outputin an appropriate amount in order to maintain the desired temperaturedelivered at the sensor 346. A multiplexer can be included to measurecurrent, voltage and temperature, at the sensor 346, and energy can bedelivered to RF electrode 314 in monopolar or bipolar fashion.

Controller 404 can be a digital or analog controller, or a computer withsoftware. When controller 404 is a computer it can include a CPU coupledthrough a system bus. This system can include a keyboard, a disk drive,or other non-volatile memory systems, a display, and other peripherals,as are known in the art. Also coupled to the bus is a program memory anda data memory.

User interface and display 402 includes operator controls and a display.Controller 404 can be coupled to imaging systems including, but notlimited to, ultrasound, CT scanners, X-ray, MRI, mammographic X-ray andthe like. Further, direct visualization and tactile imaging can beutilized.

The output of current sensor 396 and voltage sensor 398 are used bycontroller 404 to maintain a selected power level at RF electrode 314.The amount of RF energy delivered controls the amount of power. Aprofile of the power delivered to electrode 314 can be incorporated incontroller 404 and a preset amount of energy to be delivered may also beprofiled.

Circuitry, software and feedback to controller 404 result in processcontrol, the maintenance of the selected power setting which isindependent of changes in voltage or current, and is used to change thefollowing process variables: (i) the selected power setting, (ii) theduty cycle (e.g., on-off time), (iii) bipolar or monopolar energydelivery; and, (iv) fluid delivery, including flow rate and pressure.These process variables are controlled and varied, while maintaining thedesired delivery of power independent of changes in voltage or current,based on temperatures monitored at sensor 346.

Referring now to FIG. 31, current sensor 396 and voltage sensor 398 areconnected to the input of an analog amplifier 410. Analog amplifier 410can be a conventional differential amplifier circuit for use with sensor346. The output of analog amplifier 410 is sequentially connected by ananalog multiplexer 412 to the input of A/D converter 414. The output ofanalog amplifier 410 is a voltage which represents the respective sensedtemperatures. Digitized amplifier output voltages are supplied by A/Dconverter 414 to microprocessor 394. Microprocessor 394 may be a type68HCII available from Motorola. However, it will be appreciated that anysuitable microprocessor or general purpose digital or analog computercan be used to calculate impedance or temperature.

Microprocessor 394 sequentially receives and stores digitalrepresentations of impedance and temperature. Each digital valuereceived by microprocessor 394 corresponds to different temperatures andimpedances.

Calculated power and impedance values can be indicated on user interfaceand display 402. Alternatively, or in addition to the numericalindication of power or impedance, calculated impedance and power valuescan be compared by microprocessor 394 to power and impedance limits.When the values exceed predetermined power or impedance values, awarning can be given on user interface and display 402, andadditionally, the delivery of RF energy can be reduced, modified orinterrupted. A control signal from microprocessor 394 can modify thepower level supplied by energy source 392.

FIG. 32 illustrates a block diagram of a temperature and impedancefeedback system that can be used to control the delivery of energy totissue site 416 by energy source 392 and the delivery of coolingsolution to electrode 314 and/or tissue site 416 by flow regulator 418.Energy is delivered to RF electrode 314 by energy source 392, andapplied to tissue site 416. A monitor 420 ascertains tissue impedance,based on the energy delivered to tissue, and compares the measuredimpedance value to a set value. If the measured impedance exceeds theset value, a disabling signal 422 is transmitted to energy source 392,ceasing further delivery of energy to RF electrode 314. If measuredimpedance is within acceptable limits, energy continues to be applied tothe tissue.

The control of cooling solution 70 to electrode 314 and/or tissue site416 is done in the following manner. During the application of energy,temperature measurement device 408 measures the temperature of tissuesite 416 and/or RF electrode 314. A comparator 424 receives a signalrepresentative of the measured temperature and compares this value to apre-set signal representative of the desired temperature. If the tissuetemperature is too high, comparator 424 sends a signal to a flowregulator 418 (connected to an electronically controlled micropump, notshown) representing a need for an increased cooling solution flow rate.If the measured temperature has not exceeded the desired temperature,comparator 424 sends a signal to flow regulator 418 to maintain thecooling solution flow rate at its existing level. The foregoingdescription of a preferred embodiment of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formsdisclosed. Obviously, many modifications and variations will be apparentto practitioners skilled in this art. It is intended that the scope ofthe invention be defined by the following claims and their equivalents.

1. A method of treating tissue regions at or near the lower esophagealsphincter comprising the steps of providing an expandable structurecarrying an energy delivery device, the structure having a non-deployedstate and a deployed state, introducing the structure in thenon-deployed state through an esophagus to a first tissue regioncomprising the cardia of the stomach, expanding the structure to thedeployed state in the first tissue region, delivering sufficient energyfrom the energy delivery device to create a lesion in the interior ofthe first region, collapsing the structure to the non-deployed state,moving the structure in the non-deployed state from the first tissueregion to a second tissue region comprising the lower esophagealsphincter, delivering sufficient energy from the energy delivery deviceto create a lesion in the interior of the second tissue region,collapsing the structure to the non-deployed state, and removing thestructure from the esophagus, whereby a pattern of lesions is formed inthe first and second tissue regions to create a desired tissue effect.2. A method according to claim 1 wherein the desired tissue effectincludes a reduction in a duration of lower esophageal sphincterrelaxation.
 3. A method according to claim 1 wherein the desired tissueeffect includes a reduction in a frequency of reflux of stomach contentsinto the esophagus.
 4. A method according to claim 1 wherein the desiredtissue effect includes a reduction of a frequency of a symptom of refluxof stomach contents into the esophagus.
 5. A method according to ofclaim 1 wherein the desired tissue effect includes a reduction of anincidence of a sequela of reflux of stomach contents into the esophagus.6. A method according to claim 1 wherein the desired tissue effectincludes a tightening of the lower esophageal sphincter.
 7. A methodaccording to claim 1, further comprising introducing a fluid to at leastone of the first and second tissue regions.
 8. A method according toclaim 1 wherein the energy delivery device comprises an RF needleelectrode.
 9. A method according to claim 1 wherein the desired tissueeffect includes blocking of an electrical conduction pathway in at leastone of the esophagus, the lower esophageal sphincter, and the cardia.10. A method according to claim 1 wherein the desired tissue effectincludes ablating an electrical pathway in at least one of theesophagus, the lower esophageal sphincter, and the cardia.
 11. A methodaccording to claim 1 wherein the desired tissue effect includes ablatingan electrical foci in at least one of the esophagus, the loweresophageal sphincter, and the cardia.
 12. A method according to claim 1wherein the desired tissue effect includes inducing necrosis of anelectrical conduction pathway in at least one of the esophagus, thelower esophageal sphincter, and the cardia.
 13. A method according toclaim 1 wherein the expandable structure is a basket assembly comprisinga first arm, a second arm, and a third arm coupled together.